I have 16 different options in my program and i have a 16 character variable which is filled with 1's or 0's depending on the options that are selected (0000000000000000 means nothing is selected, 0010101010000101 means options 3,5,7,9,14 and 16 are selected, 1111111111111111 means everything is selected.)
When i run my program, the code looks (using an if statement) for a 1 in the designated character of the 16 digit number and if there is one there then it runs the code for that option, otherwise it skips it..
e.g option 3 looks too see if the 3rd character (0010000000000000) is a 1 and if it is it runs the code.
Now what i am trying to do is generate a list of every different combination that is possible so I can create an option for it to just loop through and run every possible option:
0000000000000001
0000000000000010
0000000000000011
...
1111111111111100
1111111111111110
1111111111111111
I have tried this but i think it may take a couple of years to run jaja:
Dim binString As String
Dim binNUM As Decimal = "0.0000000000000001"
Do Until binNUM = 0.11111111111111111
binString = binNUM.ToString
If binString.Contains(1) Then
If binString.Contains(2) Or binString.Contains(3) Or binString.Contains(4) Or binString.Contains(5) Or binString.Contains(6) Or binString.Contains(7) Or binString.Contains(8) Or binString.Contains(9) Then
Else
Debug.Print(binNUM)
End If
End If
binNUM = binNUM + 0.0000000000000001
After the code above is complete i would then take the output list and remove any instances of "0." and then any lines which had fewer than 16 chararcters (because the final character would be a 0 and not show) I would add a 0 until there was 16 characters. I know this bit might be stupid but its as far a ive got
Is there a faster way I can I generate a list like this in VB.net?
You should be able to get the list by using Convert.ToString as follows:
Dim sb As New System.Text.StringBuilder
For i As Integer = 0 To 65535
sb.AppendLine(Convert.ToString(i, 2).PadLeft(16, "0"c))
Next
Debug.Print(sb.ToString())
BTW: This should finish in under one second, depending on your system ;-)
Create an enum with FlagAttributes, which allows you to do the key functions you list. Here is an example of setting it up in a small project I am working on:
<FlagsAttribute>
Public Enum MyFlags As Integer
None = 0
One = 1
Two = 2
Three = 4
Four = 8
Five = 16
Recon = 32
Saboteur = 64
Mine = 128
Headquarters = 256
End Enum
e.g.
Dim temp as MyFlags
Dim doesIt as Boolean
temp = MyFlags.One
doesIt = temp.HasFlag(MyFlags.Two)
temp = temp OR MyFlags.Three
'etc.
The real advantage is how it prints out, if you want something other than 0, 1 and is much more human friendly.
Related
I have this integer. A = 100002 of 6 digits and i want to add 2 extra 0 in the middle so it can be a integer of 8 digits.
Result = 10000002
how can i do it?
You can split your number up into two parts, the left and the right side. Then add the zeros to the left side and put back the right side.
100002 -> 100 [left side] 002 [right side]
Dim number As Integer = 100002
Dim rightSide As Integer = number Mod 1000
Dim leftSide As Integer = number - rightSide
leftSide *= 100 ' Add zeros
Dim newNumber As Integer = leftSide + rightSide
With this, 123456 will become 12300456.
There are lots of different ways to answer this, meaning that your question is likely not specific enough to get the answer you want. For example, the_lotus's answer is of course correct (and a more practical solution, too). However, this solution will also yield the result you specify in the simplest possible manner, by subtracting 2, multiplying by 100, and adding 2 again:
Result = (A - 2) * 100 + 2
Since both of these very different methods solve the problem you have posed, it follows that you might want to pose the problem a bit more carefully. For example, if you want to work with numbers other than 100002 (which you haven't said that you do), this solution of course won't allow that. If you want a solution that applies to numbers with other than six digits, the_lotus's solution won't allow that in all cases, either.
if we write 12wkd3, how to choose/filter 123 as integer in octave?
example in octave:
A = input("A?\n")
A?
12wkd3
A = 123
while 12wkd3 is user keyboard input and A = 123 is the expected answer.
assuming that the general form you're looking for is taking an arbitrary string from the user input, removing anything non-numeric, and storing the result it as an integer:
A = input("A? /n",'s');
A = int32(str2num(A(isdigit(A))));
example output:
A?
324bhtk.p89u34
A = 3248934
to clarify what's written above:
in the input statement, the 's' argument causes the answer to get stored as a string, otherwise it's evaluated by Octave first. most inputs would produce errors, others may be interpreted as functions or variables.
isdigit(A) produces a logical array of values for A with a 1 for any character that is a 0-9 number, and 0 otherwise.
isdigit('a1 3 b.') = [0 1 0 1 0 0 0]
A(isdigit(A)) will produce a substring from A using only those values corresponding to a 1 in the logical array above.
A(isdigit(A)) = 13
that still returns a string, so you need to convert it into a number using str2num(). that, however, outputs a double precision number. so finally to get it to be an integer you can use int32()
How do I make a biased random number generator (RNG) in VB.NET?
I know I could make it by fiddling with the output of the Randomize()/Rnd methods, but is there a built-in way of doing this?
I want the biased RNG to give me either a 2 or 4 (though using 1 or 2 as a substitute is also OK by me), with 2 occurring on average 90% of the time and 4 occurring on average 10% of the time.
Create a random number generator to return values from 1-10, if the value from the random number generator is between 1 and 9 send a 2 if the value is 10 send a 4.
You might want to look at this
http://msdn.microsoft.com/en-us/library/vstudio/ctssatww(v=vs.100).aspx?cs-save-lang=1&cs-lang=vb#code-snippet-2
If you want to come out with a mask to generate your values
Here is what I think you can do.
Dim numbers() as integer = {2,2,2,2,4,2,2,2,2,2} ' set 10% for 4, 90% for 2
Dim r as new Random()
Return numbers(r.Next(0, 10))
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.
Closed 10 years ago.
Hi, I am new to Visual Basic, I have a project where I need to be able to manipulate individual bits in a value.
I need to be able to switch these bits between 1 and 0 and combine multiple occurrences of bits into one variable in my code.
Each bit will represent a single TRUE / FALSE value, so I'm not looking for how to do a single TRUE / FALSE value in one variable, but rather multiple TRUE / FALSE values in one variable.
Can someone please explain to me how I can achieve this please.
Many thanks in advance.
Does it have to be exactly one bit?
Why don't you just use the actual built in VB data type of Boolean for this.
http://msdn.microsoft.com/en-us/library/wts33hb3(v=vs.80).aspx
It's sole reason for existence is so you can define variables that have 2 states, true or false.
Dim myVar As Boolean
myVar = True
myVar = Flase
if myVar = False Then
myVar = True
End If
UPDATE (1)
After reading through the various answers and comments from the OP I now understand what it is the OP is trying to achieve.
As others have said the smallest unit one can use in any of these languages is an 8 bit byte. There is simply no order of data type with a smaller bit size than this.
However, with a bit of creative thinking and a smattering of binary operations, you can refer to the contents of that byte as individual bits.
First however you need to understand the binary number system:
ALL numbers in binary are to the power of two, from right to left.
Each column is the double of it's predecessor, so:
1 becomes 2, 2 becomes 4, 4 becomes 8 and so on
looking at this purely in a binary number your columns would be labelled thus:
128 64 32 16 8 4 2 1 (Remember it's right to left)
this gives us the following:
The bit at position 1 = 1;
The bit at position 2 = 2;
The bit at position 3 = 4;
The bit at position 4 = 8;
and so on.
Using this method on the smallest data type you have (The byte) you can pack 8 bit's into one value. That is you could use one variable to hold 8 separate values of 1 or 0
So while you cannot go any smaller than a byte, you can still reduce memory consumption by packing 8 values into 1 variable.
How do you read and write the values?
Remember the column positions? well you can use something called Bit Shifting and Bit masks.
Bit Shifting is the process of using the
<<
and
>>
operators
A shifting operation takes as a parameter the number of columns to shift.
EG:
Dim byte myByte
myByte = 1 << 4
In this case the variable 'myByte' would become equal to 16, but you would have actually set bit position 5 to a 1, if we illustrate this, it will make better sense:
mybyte = 0 = 00000000 = 0
mybyte = 1 = 00000001 = 1
mybyte = 2 = 00000010 = (1 << 1)
mybyte = 4 = 00000100 = (1 << 2)
mybyte = 8 = 00001000 = (1 << 3)
mybyte = 16 = 00010000 = (1 << 4)
the 0 through to 16 if you note is equal to the right to left column values I mentioned above.
given what Iv'e just explained then, if you wanted to set bits 5, 4 and 1 to be equal to 1 and the rest to be 0, you could simply use:
mybyte = 25(16 + 8 + 1) = 00011001 = (1 << 4) + (1 << 3) + 1
to get your bits back out, into a singleton you just bit shift the other way
retrieved bit = mybyte >> 4 = 00000001
Now there is unfortunately however one small flaw with the bit shifting method.
by shifting back and forth you are highly likely to LOOSE information from any bits you might already have set, in order to prevent this from happening, it's better to combine your bit shifting operations with bit masks and boolean operations such as 'AND' & 'OR'
To understand what these do you first need to understand simple logic principles as follows:
AND
Output is one if both the A and B inputs are 1
Illustrating this graphically
A B | Output
-------------
0 0 | 0
0 1 | 0
1 0 | 0
1 1 | 1
As you can see if a bit position in our input number is a 1 and the same position in our input number B is 1, then we will keep that position in our output number, otherwise we will discard the bit and set it to a 0, take the following example:
00011001 = Bits 5,4 and 1 are set
00010000 = Our mask ONLY has bit 5 set
if we perform
00011001 AND 0010000
we will get a result of
00010000
which we can then shift down by 5
00010000 >> 5 = 00000001 = 1
so by using AND we now have a way of checking an individual bit in our byte for a value of 1:
if ((mybyte AND 16) >> 1) = 1 then
'Bit one is set
else
'Bit one is NOT set
end if
by using different masks, with the different values of 2 in the right to left columns as shown previously, we can easily extract different singular values from our byte and treat them as a simple bit value.
Setting a byte is just as easy, except you perform the operation the opposite way using an 'OR'
OR
Output is one if either the A or B inputs are 1
Illustrating this graphically
A B | Output
-------------
0 0 | 0
0 1 | 1
1 0 | 1
1 1 | 1
eg:
00011001 OR 00000100 = 00011101
as you can see the bit at position 4 has been set.
To answer the fundamental question that started all this off however, you cannot use a data type in VB that has any resolution less than 1 byte, I suspect if you need absolute bit wise accuracy I'm guessing you must be writing either a compression algorithm or some kind of encryption system. :-)
01010100 01110010 01110101 01100101, is the string value of the word "TRUE"
What you want is to store the information in a boolean
Dim v As Boolean
v = True
v = False
or
If number = 84 Then ' 84 = 01010100 = T
v = True
End If
Other info
Technicaly you can't store anything in a bit, the smallest value is a char which is 8 bit. You'll need to learn how to do bitwise operation. Or use the BitArray class.
VB.NET (nor any other .NET language that I know of) has a "bit" data type. The smallest that you can use is a Byte. (Not a Char, they are two-bytes in size). So while you can read and convert a byte of value 84 into a byte with value 1 for true, and convert a byte of value 101 into a byte of value 0 for false, you are not saving any memory.
Now, if you have a small and fixed number of these flags, you CAN store several of them in one of the integer data types (in .NET the largest integer data type is 64 bits). Or if you have a large number of these flags you can use the BitArray class (which uses the same technique but backs it with an array so storage capacity is greater).
I'm programming a basic slot machine in Visual basic, and want to use a for loop to randomly choose the image for each slot, display the image in each slot, and change the slotName variable (so I can check later on which symbols are in the slots) for each slot.
The problem I'm finding with a for loop is that the variables and objects for each slot have different names (slot1Name, slot2Name, slot3Name, lblSlot1, lblSlot2, lblSlot3, etc). Is there any way I could have something like:
currentSlotName = "slot" & i & "Name"
This is the code at the moment, this code is repeated (with different variable and object names), for each of the 3 slots, which is pretty inefficient. How can I tidy this code up?
' Randomise numbers and assign images to slots based on random numbers, if the hold isn't on
' Slot 1
If Not held1 Then
slot1Value = Int(Rnd() * numbersGenerated + 0.5)
Select Case slot1Value
Case 0 To 5
lblSlot1.Image = imgBanana
slot1Name = "Banana"
Case 6 To 11
lblSlot1.Image = imgOrange
slot1Name = "Orange"
Case 12 To 16
lblSlot1.Image = imgCherries
slot1Name = "Cherries"
Case 17 To 19
lblSlot1.Image = imgSeven
slot1Name = "Seven"
Case 20
lblSlot1.Image = imgBatman
slot1Name = "Batman"
Case Else
lblSlot1.Text = "Error. slot1value = " & slot1Value
End Select
End If
I have searched around for this, but I'm very new to Visual Basic, and want to keep my code as simple as possible.
Too much to explain. Arrays is what you need to learn next.
http://msdn.microsoft.com/en-us/library/wak0wfyt.aspx